There were 630 T-shirts at a store. ³₇ of them were without collars. T-shirts without collars were priced at $4 each. T-shirts with collars were priced at $7 each. The store owner sold ²₃ of the T-shirts without collars and ⁷₈ of the T-shirts with collars. How much did he collect from all the T-shirts he sold?
Number of T-shirts = 7 u

7 u = 630

1 u = 630 ÷ 7 = 90

Number of T-shirts without collars
= 3 u
= 3 x 90
= 270

Number of T-shirts without collars sold 
= ²₃ x 270
= 180

Number of T-shirts with collars
= 4 u
= 4 x 90
= 360

Number of T-shirts with collars sold
= ⁷₈ x 360
= 315

Amount that the store owner collected from the sale of the T-shirts without collars
= 180 x 4
= $720

Amount that the store owner collected from the sale of the T-shirts with collars
= 315 x 7
= $2205

Total amount that the store owner collected from all the T-shirts he sold
= 720 + 2205
= $2925

Answer(s): $2925